Air conditioned display compartment



y K. w. HALL ETAL, 241,54

AIR CONDITIONED DISPLAY COMPARTMENT Filed May 21, 1938 2 Sheets-Sheet lCONDH'IONINC: *j

APDAQATUS INVENTORS ATTORN EYS May 13, 1941. K. w. HALL ETAL 2924,8541

AIR CONDITIONED DISPLAY COMPARTMENT Filed May 21, 1938 2 Sheets-Sheet 2KsW/z M/ Aw EQZ m 0 w w 0 BY wi /44% W MM ATTORN EYS Patented May 13,1941 2.241.854 V AIR. CONDITIONED DISPLAY oom'anrmm'r Keith W. Hall. andDonald W. McCready, Ann Arbor, Mich; said Hall assignor to 'lolco, Inc.,Toledo, Ohio, a corporation of Ohio Application May a1, 1938, Serial No.209,393

4Claims.

The invention relates to air conditioned compartments suitable for thedisplay in retail stores of products of the soil, cigars, and otherproducts that require a humid or refrigerated atmosphere. In theretailing of products that are displayed in bulk it has been foundhighly desirable that masses of the products be kept fully visible anduninclosed so that customers may handle them. For example, mostconsumers visit more I than one food store, so that rapidly movinproducts such as fruit and vegetables-are sold in greatest quantities bythe stores that provide the most effective displays. It is universallyfound that a retailer sells more of such products by displaying them onopen racks than by displaying them behind glass, because an urge to buyis fostered by displaying the products out in the open where thecustomer can reach out and pick them up. Many perishable products,however, suffer rapid deterioration when kept in the open air. Someproducts must be kept at low temperatures, and other products, such asvegetables, must be surrounded by humid air to prevent them from dryingout and thereby losing their freshness.

The principal object of the invention is to provide a displaycompartment in which products may be openly displayed and yet surroundedby properly conditioned air. More specific objects and advantages areapparent from the description, in which reference is had to accompanyingdrawings illustrating a preferred embodiment o the invention. I

Fig. I of the drawings is a perspective of an apparatus provided withdisplay compartments.

embodying the invention, with portions of the apparatus broken away toshow its interior construction.

Fig. II is a fragmentary vertical section taken on the line IIII of Fig.I.

Fig. III is a fragmentary vertical section taken on the line III-III ofFig. II.

Fig. IV is a fragmentary horizontal section taken on the line IV--IV ofFig. III.

Fig. V is a fragmentary vertical section taken on the line VV of Fig. I.

Fig. VI is a fragmentary section on an inclined plane taken on the lineVIVI of Fig. V.

These specific drawings and the specific description which followsmerely disclose and illustrate the invention and are not intended toimpose limitations upon the claims. 1

When conditioned air is supplied to products on an ordinary open displayrack, the eddies and convection currents that normally exist in the roommix with and dilute the conditioned m" and sweep it away from thesurface of the products with surprising rapidity, so as to destroy anyprotection that might be afforded to the products by the conditionedair. In accordance with the invention, products on display are keptsurrounded by conditioned air in a display compartment having an accessopening, means for directing a stream of air to form a protectivecurtain that shields the opening, and means for supplying conditionedair to the compartment. Since conditioned air is continuously suppliedto the compartment, there is a continuous exhausting of air from thecompartment through the access opening. It has been discovered that itis not necessary to supply an excessive quantity of conditioned air inorder to protect perishable products in a compartment embodying theinvention. When the conditioned air supplied to the compartment has ahigh moisture content, products in the compartment can be adequatelyprotected without exhausting so much" humid air as to steam up the room.The discharge of a certain amount of conditioned air into the roomcannot be avoided, but the volume of air so discharged can be reduced,ifdesired, by withdrawing from the display compartment and recirculatingback to the air conditioning apparatus a portion of the conditioned airsupplied to the compartment.

For products requiring a humid atmosphere, the relative humidityin thecompartment can be maintained substantially higher than that ordinarilyprevailing in the surrounding atmosphere. The air inside the compartmentcan also be kept at a temperature considerably below the temperature inthe room. When refrigerated air is supplied to an ordinary open rack, itis heated up as fast as it is supplied, because the rack is fullyexposed. As the refrigerated air becomes warmer in passing amongproducts on the rack, its relative humidity falls rapidly, so thatrefrigerated air supplied to an ordinary open rack has a particularlysevere effect upon products that are easily dehydrated, such asvegetables. A compartment embodying the invention is advantageous inthat it prevents refrigerated air that is supplied to the compartmentfrom being heated up while it is still in contact with the products. Theconditioned air in the compartment can be kept at the desired lowtemperature if the conditioned air is supplied at the proper rate,because the entry of atmospheric air into the compartment issubstantially prevented.

In the displaying of fruits and vegetables it is possible to obtainquite satisfactory results by simply humidifying the air that issupplied to the compartment. The air supplied to fruits and vegetablesshould be highly humidified, and

. the cooling which is incident to the humidiflcation may cause areduction of 5 to 20 degrees Fahrenheit in the temperature of the air.However, air taken into a humidifier cannot be cooled below its wet bulbtemperature. Since the wet bulb temperature of the entering air isalways higher than its dew point, the temperature to which the airsupply is cooled by merely humidifying it is above the dew point of thesurrounding atmosphere.

When the only cooling employed is the cooling incident to thehumidiflcation of the air supply, therefore, condensation in and aroundthe display compartment does not occur. In the displaying of fruit andvegetables the prevention of condensation is particularly desirable,because produce becomes slimy and discolored when it is kept wet. Theattempts that have heretofore been made to protect produce on display byspraying water upon it have failed because of the discoloration andsliming that was produced. The present invention afiords an importantadvantage in that it makes it possible to protect fruit and vegetablesagainst dehydration without keeping them wet. Humid air that is suppliedto the present compartment is preferably 4 I quite free from particlesof liquid'water. If parby this excessive handling. In contrast, adisplay compartment embodying the invention may simply be covered atnight or at any other time when the products are not being displayed.While the compartment is covered, the discharge of conditioned air intothe atmosphere may be reduced, so that the room will not be steamed upwhile there is no one entering or leaving through the door and thereforelittle ventilation. The compartment may be covered by simply throwing apiece of canvas over it.

The protective curtain of air that shields the opening into the presentcompartment is discharged in the form of a substantially continuoussheet of rapidly moving air. Any eddies or drafts that might causeatmospheric air to enter the compartment are overcome by the air cur-'tain, so that dilution of the conditioned air in the compartment byatmospheric air is inhibited.

The sheet of moving air formingthe curtain is 1 narrowest near the pointof discharge, because the sheet 01 moving air tends to become wider andwider as additional air is entrained. In

fact, the air curtain consists not of air moving in a single directionbut air moving with considerable turbulence.

When the air curtain is directed across the compartment opening, itentrains air from the compartment on one side and air from theatmostinuous loss of air from tr compartment because of the entrainingaction of the air curtain. If this loss of air occurs at a ratesubstantially greater than the rate at which conditioned air is suppliedto the compartment, there may be a tendency for atmospheric air to flowinto the compartment. Therefore the conditioned air is preferablysupplied to the compartment at a rate substantially as great as the lossof air from the compartment caused by the curtain of air. When thecurtain of air is so directed that it does not enter the compartment,the temperature or humidity of the air discharged to form the curtain isnot material, and the air used for the curtain need not be conditioned.However, it may be convenient to use conditioned air for the curtain ifa supply of conditioned air under pressure is available. Even whenconditioned air is employed for the curtain, the discharge ofconditioned air from a group of compartments providing ample capacityfor a store of ordinary size is not suiiicient to cause excessivehumidiflcation of the store.

- The drawings show an apparatus that is particularly suitable fordisplaying fruit and vege tables. The apparatus is made up of severalidentical sections, each containing two superimposed displaycompartments, and any desired number of sections may be employed. Fig. Ishows a complete section and a portion of each of the twoadjacentsections.

The main supporting members of each section are its two'side' panelsIII, which rest upon the floor and are tied together at the front bymeans of a reinforcing bar H. The rear wall 12 of each section issecured to the side panels l0, and has its lower edge turned inward toform a flange I3. Resting upon the flange l3 and the reinforcing bar His a plate l4 closing the bottom of the section. Upon the plate Il maybe placed baskets containing a reserve supply of produce to bedisplayed. The masses of produce in the display compartments becomedepleted as the produce is sold. Thus it is desirable to have thereserve supply of produce handy sothat an attractive massive display canbe maintained by continuously replenishing the display compartments.

In front of the baskets stored in the lower portion of the section is aremovable front panel I 5.

Conditioned air to protect the produce stored inbaskets in the lowerportion of the section is supplied from a main air duct l6 throughperforations I! in the bottom of the duct. The rear wall I! of thesection slopes forward beneath the air duct It to direct any water thatdrips from the air duct toward a gutter l8 formed in the rear wall l2(see Fig. II). Perforations. is are formed in the bottom of the gutterl8 to discharge the water into a sloping trough 20 secured to the backof the rear wall l2. troughs 20 of the several sections overlap and areso inclined that the water flows from trough to trough. v'Ihus thetrough 20 of only one of the sections needs to be provided with a drainconnection, and this trough receives water from all the other troughs.

Fig. IV shows how the sectional ducts l6 are formed into a singlecontinuous air duct. Each of the sections l6 has an outwardly turnedflange 2| surrounding each of its ends. It should be noted that theflange 2| is turned upward instead of downward at the bottom of the ductso that it forms a dam to prevent water from flowing from one section toanother. A connecting sleeve The sloping 22 telescopes within theadjacent ends of the two sectional ducts I3, and a rubber gasket 23surrounding the connecting sleeve 22 is compressed and seals theconnection when the two adjacent sections are pushed together. A bolt 24assists in holding the ends of the adjacent sectional ducts together.

At the front of the sections each pair of adjacent side panels I areheld apart by means of channel-shaped spacers 25 (see Fig. VI) fiecuredto the spacers 25 by means of screws 26 are decorative strips 21 thatconceal the edges of the side panels ID. The side panels of each sectionsupport a pan 29 which closes in the top of the bottom compartment inwhich the baskets are stored. Dovetailing with the front edge of the pan29 is a suitably shaped ledge 29, to the bottom of which is hinged aswinging door 30. In the left-hand section in Fig. I the swinging door30 is shown in its uppermost position in which it may be held by asuitable catch. The doors 30 in the other two sections in Fig. I areshown in their closed positions.

In front of the main air duct 16 in each section is a distributingchamber 3| through which fiows the air that forms the curtains whichprotect the display compartments. The top of the distributing chamber 3|is closed by an upper pan 32 similar to the lower pan 28. Immediatelybelow the upper pan 32 is a sheet 33, which with the pan 32 forms a fiatduct for leading the air forward from the distributing chamber 3|. Anupper ledge 34, somewhat similar to the lower ledge 29, dovetails withthe front edge of the upper pan 32, and the air curtain protecting theupper display compartment is discharged past the front edge of the upperledge 34 (see Fig. V). The lower wall of the flat air passage iscontinued by a suitably formed strip 35 dovetailing with the front edgeof the sheet 33. The air curtain that protects the lower displaycompartment is discharged past the front edge of the strip 35.

Closing the flat air passage at its'front end are an upper closure strip36 and a lower closure strip 31. The upper closure strip is separatedfrom the upper ledge 34 by means of a spacer 38 to form the dischargeslot for the upper air curtain. Similarly the lower closure strip 31 isseparated from the adjacent strip 35 to form the discharge slot for thelower air curtain. In the construction shown most of the air tends topass through the lower discharge slot, so that an adjustable plate 39 isprovided for partially obstructing the lower discharge slot. If thebolts supporting the adjustable plate 39 are loosened, they may be slidforward or backward in slots provided in the strip 35 to apportion theamounts of air discharged to form the upper and lower air curtains. Y

The total volume of air discharged to form the air curtains is regulatedby means of a slidable metering plate 40 (see Fig. II). The meteringplate 49 is held against the main duct l6 by means of guides 4|, and itcan be shifted by means of a channel-shaped bracket 42 secured to thefront of the metering plate and provided with a handle 43, In theoperation of the device the handle 43 may be positioned in any one offour notches 44 (see Fig. III). The arrangement of the orifices in themetering plate 40 and the corresponding orifices in the front wall ofthe main air duct I is such that the metering plate 40 in each of itsfour positions uncovers a different number of the orifices in the mainduct. Fig. III shows the metering plate 40 in its extreme right-handposition. so that all the orifices in the main duct are uncovered. Whenthe metering plate 40 is in its extreme left-hand position, all of theorifices are closed.

As shown in Fig. I, the sheet 33 forms the top of thelower displaycompartment, and a cover plate 45 forms the top of the upper displaycompartment. Electric lights may be secured beneath the sheet 33 and thecover plate 45 at a point near the front where they are concealed.Produce in the upper and lower display compartments is supported uponperforated plates 43, the front edges of which rest upon the upper ledge34 and the lower ledge 29. Atv their rear edges the perforated plates 46are supported by hooks 41, and hooks are provided at various levels sothat the perforated plates can be supported at any desired angle.

Conditioned air is supplied to the display compartments through suitableorifices 43 in the main air ducts I5, and the conditioned air flowsupward through each perforated plate and through the bed of produceresting upon the plate. Conditioned air is supplied to the main duct I 6from any suitable air conditioning apparatus, and the air in the mainduct should be kept under a slight pressure which is substantiallyconstant. The volume of conditioned air supplied to the displaycompartments may then be regulated by employing orifices 48 of theproper size. The orifices 48 offer such a restricted passage for the airthat the frictional resistance met by the air as it passes through theorifices is considerably greater than the resistance offered to the airby the perforated plates 46 and the bed of produce thereabove. Thus theorifices 48 meter the flow of air, and the volume of air supplied to acompartment is substantially constantwhether the compartment is filledwith produce or empty. The orifices 48 offer so much frictionalresistance to the air that variations in the amount of produce in thecompartment do not materially change the total resistance that the airmust overcome in flowing from the duct it through the bed of produce.Similarly the orifices i'l meter the air that flows into the bottomcompartment where the reserve produce is stored in baskets. be suppliedto the duct l6 under a sufiicient pressure so that the desired quantityof air fiows through the-orifices. In the illustrated apparatus theorifices meter the flow of air so that it is only necessary to supplythe air to the main duct at the proper constant pressure. Any othersuitable arrangement for supplying the air at the correct rate may beemployed if desired.

The air curtains indicated by arrows in Fig. I

I are directed slightly outward and do not enter the displaycompartments. They entrain air from the display compartments, and theconditioned air should be supplied to the compart: ments through theorifices 48 at a rate substan-. tially as great as the loss of air fromthe compartments caused by the air curtains. If the loss of air byentrainment is not made up by supplying suflicient air through theorifices 49, air will tend to enter the compartments from theatmosphere. I

The air flowing through the orifices 48 impinges against baiile strips49 secured upon posts 50 by means of screws 5|. The sharp deflection ofthe air that occurs when it strikes the baille strips 49 causes theprecipitation of any mist that the air may contain. Moisture drippingfrom the baflie strips 49 collects in the pans 23 and 32,

Conditioned air must which have upturned rear and side edges 52 (seeFigs. II and III) The upturned edges 52 of the pans compress a rubbergasket 53 against the main duct I and the side panels Hi to produce awater-tight joint. An upper drain spout 54 leads the water from theupper pan 32 to the lower pan 28. Water from the lower pan 28 is I ledinto the trough 20 through a lower drain spout 55, the inlet of which isprotected by a drain guard 55.

Each of the display compartments is divided into two parts by means of apartition 51. It should be noted that the front of the section slopes,particularly in its upper part, so that the fronts of the displaycompartments are inclined backward. The inclined fronts produce maximumvisibility of the products in the compartments, making it possible toemploy openings in the compartment fronts that are not unduly large.

It should be noted that the conditioned air that is used for the aircurtains tends to cool the bottom of the upper display compartment andthe top of the lower display compartment. Unconditioned air would formequally effective air curtains, but a duct leading relatively warm airto the slots from which the air curtains are discharged would have to besuitably insulated.

'The rear wall l2 behind the display compartments and the main duct i5is covered with insulation' 58. It should be noted that the apparatusshown in the drawings is designed to operate at only to 20 degrees belowthe temperature of the surrounding atmosphere. For lower temperaturesadditional insulation may be used underneath the cover plate 45,underneath the bottom plate I 4 of the lower compartment, and againstthe back of the rear wall behind the bottom compartment.

When the door 301s shut, the bottom compartment is completely closed in.The sides of the bottom compartment are formed by the side panels I. Asmall area at each side of the section just under the main air duct i6is not covered by the side panels I0 but by a plate 59, secured to theside panels III by means of screws 50. The apparatus may be finished inpol celain enamel or any other suitably resistant finish.

It is recommended that the air supplied to the main ductlli be air thathas been withdrawn from the atmosphere and passed through a humidifierwithout any cooling other than that incident to the humidification. Arelative humidity of 90 to 95 per cent is preferable. The

air may be forced upward through each square foot of the perforatedplates 46 at a rate of 100 to 250 cubic feet per hour. The air curtainsare preferably made up of a discharge of air at about 600 cubic feet perhour per foot of length of the curtains, flowing at a discharge velocityof about When produce in the compartments is not being displayed tocustomers, a cloth may be thrown over the apparatus to close the displaycompartments. While 'the compartments are covered with a cloth, themetering plate 40 may be shifted to its extreme left-hand position, andthe conditioned air may be supplied to the main duct It at a reducedpressure if desired.

The embodiments of the invention that have been disclosed may bemodified to meet various requirements.

Having described our invention, we claim:

1. In an apparatus of the class described, in combination, a displaycompartment having walls for enclosing a space extending to asubstantial height above products displayed therein and having an accessopening, means for directing a stream of air to form a protectivecurtain of air that shields said opening, and means for continuouslysupplying conditioned air to the compartment, whereby said conditionedair, continuously escapes through said access opening, and the entry ofatmospheric air therethrough is inhibited.

2. In an apparatus of the class described, in combination, a displaycompartment having walls for enclosing a space extending to asubstantial height above products displayed therein and having an accessopening, means for directing a stream of air to form a protectivecurtain of air that shields said opening but does not enter thecompartment, and means for continuously supplying conditioned air to thecompartment at a rate substantially as great as the loss of air from thecompartment caused by said curtain of air.

3. In an apparatus of the class described, in combination, a displaycompartment having walls for enclosing a space extending to asubstantial height above products displayed therein and having anopening suflicient for ready access to productsin the compartmentthrough which they are displayed, means for directing a stream of air toform a protective curtain that,

flows substantially across said opening but does not enter thecompartment, and means for continuously supplying conditioned air to thecompartment, whereby said conditioned air continuously escapes throughsaid access opening, and

the entry of atmospheric air therethrough is inhibited.

4. In an apparatus of the class described, in-

combination, a display compartment having walls for enclosing a spaceextending to a substantial height above products displayed therein andhaving an opening suflicient for ready access to products in thecompartment through which they are displayed, means for directing astream of air to form a protective curtain that flows substantiallyacross said opening but does not enter the compartment, and means forcontinuously supplying conditioned air to the compartment at a ratesubstantially as great as the loss of air from the compartment caused bysaid curtain of air.

DONALD W. McCREADY.

KEITH W.. HALL.

